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A high-efficiency strategy for resin-free and large scale liquid phase synthesis of the anti-SARS octapeptide AVLQSGFR is described. Herein, tri(4'-diphenylphosphonyloxylbenzoyl phenyl)phosphate (TDPBP) derivatives were designed as C-terminal supports to aid octapeptide intermediate purification without the need for chromatographic separation. Furthermore, the ACE inhibitory structure-activity relationship (SAR) of the anti-SARS octapeptide and its alanine-scanning analogues was systematically studied by in vitro assay and 3D-QSAR via molecular docking. This paper provides a new strategy for the development of peptide-based drugs. Simultaneously, a study on the ACE inhibition and structure-activity relationship of the anti-SARS octapeptide also lays a foundation for further understanding how the anti-SARS octapeptide acts as an ACE inhibitor.

To seek the novel application of organophosphorus compounds, the designed tri(4-formylphenyl) phosphonate (TFP) derivatives were successfully synthesized herein, which were used as C-terminal protecting groups of amino acid or greener triple-equivalent supports in liquid-phase peptide synthesis (LPPS). Through the support-aided precipitation effect of TFP derivatives, the peptide intermediates during peptide synthesis were separated and collected via rapid precipitation and facile filtration without chromatographic purification. Furthermore, the TFP derivative support can be directly recycled for reuse without further regeneration after being sheared from the target peptide.

Plecanatide is an oral guanylate cyclase-C agonist for the treatment of gastrointestinal disorders. The large-scale supply of plecanatide is restrained primarily by its industrial manufacture. Herein we developed diphenylphosphinyloxyl diphenyl ketone (DDK) derivatives as greener supports with unique precipitation-inducing properties to aid the liquid-phase total synthesis of plecanatide without the use of chromatography. Plecanatide could be obtained in high yield, and the ultimately sheared DDK derivative residue could be directly recycled or regenerated for reuse.

Nanosheet BiOI materials were synthesized using the precipitation-hydrothermal method. Subsequently, nanoparticle AgI/BiOI nanosheet composites were fabricated using an ion-exchange method and a controlled amount of BiOI. The phase composition, optical morphology, and absorption properties of the samples were determined using XRD, SEM, XPS, TEM, HRTEM, BET, and UV–Vis diffuse reflectance. Organic dyes, such as methyl orange (MO) and Coomassie brilliant blue R-250 (CBB), were used to check the composites’ photocatalytic performance undergoing photodegradation in visible light. The prepared composites had high purity, and the AgI nanoparticles were evenly loaded on the flower-like BiOI nanosheets, both absorbing the visible light. The 50% AgI NP/BiOI NS compound demonstrated the best visible photocatalytic activity and degraded rate of 96.9% and 97% of the MO and CBB dye, respectively, under visible light for 30 ​min. The photocatalytic activity of sole BiOI or AgI was poor, whereas the composites were much better. The composite with 50% AgI exhibited the best photocatalytic activity because of the formation of a heterojunction, which promotes the separation of photogenerated carriers, making AgI stable under visible-light irradiation.